Method and apparatus for charging battery

ABSTRACT

A battery charging method includes: charging a battery with a charging current; and changing the charging current in response to a current change event occurring during the charging of the battery, wherein the current change event occurs when the battery reaches a threshold voltage at which an anode potential of the battery reaches a reference value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 15/782,452filed on Oct. 12, 2017, which claims the benefit under 35 U.S.C. §119(a) of Korean Patent Application Nos. 10-2016-0144227 and 10-2017-0095510 filed on Nov. 1, 2016 and Jul. 27, 2017, respectively, in theKorean Intellectual Property Office, the entire disclosures of which areincorporated herein by reference for all purposes.

BACKGROUND 1. Field

The following description relates to a battery charging method andapparatus.

2. Description of Related Art

Various methods are used to charge a battery. For example, a constantcurrent-constant voltage (CCCV) based charging method is used to chargea battery with a constant current, and to charge the battery with aconstant voltage when a voltage of the battery reaches a preset voltage.For another example, a varying current decay (VCD) based charging methodis used to charge a battery with a high current in a low state of charge(SOC), and to charge the battery by gradually decreasing the currentwhen the SOC becomes a specific SOC.

For still another example, a fast charging method is used to reduce anamount of time used to charge a battery. In such an example, repetitionsof fast charging may degrade a life of the battery.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is this Summaryintended to be used as an aid in determining the scope of the claimedsubject matter.

In one general aspect, a battery charging method includes: charging abattery with a charging current; and changing the charging current inresponse to a current change event occurring during the charging of thebattery, wherein the current change event occurs when the batteryreaches a threshold voltage at which an anode potential of the batteryreaches a reference value.

The battery charging method may further include: verifying the thresholdvoltage corresponding to the charging current by referring to a table inwhich the threshold voltage and the charging current are stored.

The battery charging method may further include: in response to lifeinformation of the battery changing, replacing the table with a tablecorresponding to the changed life information.

The battery charging method may further include: terminating a charginginterval corresponding to the charging current, in response to thecurrent change event occurring; and charging the battery with a currentthat is less than the charging current in a subsequent charginginterval.

The battery charging method may further include: charging the batterywith a constant voltage, in response to the battery reaching a maximumvoltage; and terminating the charging of the battery, in response to thecharging current decreasing to a termination current during the chargingof the battery with the constant voltage.

The reference value may be 0.075 volts (V) to 0.73 V.

The reference value may be 0.075 V to 0.2 V.

A non-transitory computer-readable storage medium may store instructionsthat, when executed by a processor, cause the processor to perform themethod.

In another general aspect, a battery charging apparatus includes: acontroller configured to charge a battery with a charging current, andconfigured to change the charging current in response to a currentchange event occurring during the charging of the battery, wherein thecurrent change event occurs when the battery reaches a threshold voltageat which an anode potential of the battery reaches a reference value.

The controller may be further configured to verify the threshold voltagecorresponding to the charging current by referring to a table in whichthe threshold voltage and the charging current are stored.

The controller may be configured to replace the table, in response tolife information of the battery changing, with a table corresponding tothe changed life information.

The controller may be configured to terminate a charging intervalcorresponding to the charging current and to charge the battery with acurrent that is less than the charging current in a subsequent charginginterval, in response to the current change event occurring.

The controller may be configured to charge the battery with a constantvoltage in response to the battery reaching a maximum voltage, and toterminate the charging of the battery in response to the chargingcurrent decreasing to a termination current during the charging of thebattery with the constant voltage.

The reference value may be 0.075 volts (V) to 0.73 V.

The reference value may be 0.075 V to 0.2 V.

In another general aspect, a battery charging method includes: charginga battery with a first charging current; and charging the battery with asecond charging current that is less than the first charging current, inresponse to the battery reaching a threshold voltage at which an anodepotential of the battery reaches a reference value.

The reference value may be 0.075 volts (V) to 0.73 V.

The reference value may be 0.075 V to 0.2 V.

The first charging current may be greater than or equal to 1.0 C-rate.

The battery charging method may further include: verifying the thresholdvoltage corresponding to the first charging current by referring to atable in which the threshold voltage and the first charging current arestored.

The battery charging method may further include: in response to lifeinformation of the battery changing, replacing the table with a tablecorresponding to the changed life information.

The battery charging method may further include: charging the batterywith a constant voltage, in response to the battery reaching a maximumvoltage; and terminating the charging of the battery, in response to acharging current decreasing to a termination current during the chargingof the battery with the constant voltage.

In another general aspect, a battery system includes: a battery; and acontroller configured to charge the battery, in a first charging mode,with an initial charging current among charging currents stored in amemory, and in the first charging mode, change the initial chargingcurrent to a subsequent charging current, among the charging currents,in response to a voltage of the battery reaching a threshold voltagestored in the memory as corresponding to the initial charging current.The threshold voltage is a voltage at which an anode potential of thebattery reaches a reference value.

The controller may be further configured to terminate the charging ofthe battery in the first charging mode and to charge the battery with aconstant voltage in a second charging mode, in response to the voltageof the battery reaching a maximum voltage.

The controller may be further configured to terminate the charging ofthe battery in the second charging mode, in response to a chargingcurrent in the second charging mode decreasing to a termination current.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a battery system.

FIGS. 2 and 3 are diagrams illustrating an example of a battery chargingmethod.

FIGS. 4A and 4B are diagrams illustrating another example of a batterycharging method.

FIGS. 5 through 7, and 8A and 8B are diagrams illustrating examples ofmethods of determining a threshold voltage.

FIGS. 9 and 10 are diagrams illustrating another example of a method ofdetermining a threshold voltage.

FIG. 11 is a diagram illustrating an example of a battery chargingapparatus.

FIG. 12 is a diagram illustrating an example of a threshold voltagedetermining apparatus.

FIG. 13 is a diagram illustrating an example of a vehicle including abattery system.

FIG. 14 is a diagram illustrating an example of a terminal.

Throughout the drawings and the detailed description, unless otherwisedescribed or provided, the same drawing reference numerals will beunderstood to refer to the same elements, features, and structures. Thedrawings may not be to scale, and the relative size, proportions, anddepiction of elements in the drawings may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after an understanding of thedisclosure of this application. For example, the sequences of operationsdescribed herein are merely examples, and are not limited to those setforth herein, but may be changed as will be apparent after anunderstanding of the disclosure of this application, with the exceptionof operations necessarily occurring in a certain order. Also,descriptions of features that are known in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided merelyto illustrate some of the many possible ways of implementing themethods, apparatuses, and/or systems described herein that will beapparent after an understanding of the disclosure of this application.

Throughout the specification, when an element, such as a layer, region,or substrate, is described as being “on,” “connected to,” or “coupledto” another element, it may be directly “on,” “connected to,” or“coupled to” the other element, or there may be one or more otherelements intervening therebetween. In contrast, when an element isdescribed as being “directly on,” “directly connected to,” or “directlycoupled to” another element, there can be no other elements interveningtherebetween.

Throughout the specification, when an element, such as a layer, region,or substrate, is described as being “on,” “connected to,” or “coupledto” another element, it may be directly “on,” “connected to,” or“coupled to” the other element, or there may be one or more otherelements intervening therebetween. In contrast, when an element isdescribed as being “directly on,” “directly connected to,” or “directlycoupled to” another element, there can be no other elements interveningtherebetween.

As used herein, the term “and/or” includes any one and any combinationof any two or more of the associated listed items.

Although terms such as “first,” “second,” “third,” “A,” “B,” “(a),” and“(b)” may be used herein to describe various members, components,regions, layers, or sections, these members, components, regions,layers, or sections are not to be limited by these terms. Rather, theseterms are only used to distinguish one member, component, region, layer,or section from another member, component, region, layer, or section.Thus, a first member, component, region, layer, or section referred toin examples described herein may also be referred to as a second member,component, region, layer, or section without departing from theteachings of the examples.

The terminology used herein is for describing various examples only, andis not to be used to limit the disclosure. The articles “a,” “an,” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. The terms “comprises,” “includes,”and “has” specify the presence of stated features, numbers, operations,members, elements, and/or combinations thereof, but do not preclude thepresence or addition of one or more other features, numbers, operations,members, elements, and/or combinations thereof.

Unless otherwise defined, all terms, including technical and scientificterms, used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure pertains. Terms,such as those defined in commonly used dictionaries, are to beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art, and are not to be interpreted in anidealized or overly formal sense unless expressly so defined herein.

The features of the examples described herein may be combined in variousways as will be apparent after an understanding of the disclosure ofthis application. Further, although the examples described herein have avariety of configurations, other configurations are possible as will beapparent after an understanding of the disclosure of this application.

FIG. 1 is a diagram illustrating an example of a battery system 100.

Referring to FIG. 1, the battery system 100 includes a battery chargingapparatus 110 and a battery 120. The battery 120 is a battery cell, abattery module, or a battery pack.

The battery charging apparatus 110 charges the battery 120 in a stepcharging mode. The step charging mode refers to a type of a fastcharging mode, in which the battery charging apparatus 110 charges thebattery 120 by changing a charging current stepwise.

When the battery 120 is charged, an anode potential of the battery 120may be lowered due to an electrochemical phenomenon occurring in thebattery 120. When the battery 120 is being continuously charged at a lowanode potential, for example, less than or equal to 0 volts (V), anelectrode of the battery 120 may be plated with metal. For example, in acase of a lithium-ion battery, lithium plating occurs to form metalliclithium around an anode of the lithium-ion battery. Such a plating mayreduce a life of the battery 120.

To prevent plating, the battery charging apparatus 110 charges thebattery 120 by changing a charging current each time a current changeevent occurs in the step charging mode. For example, in response to avoltage of the battery 120 reaching a threshold voltage, the currentchange event may occur. In such a case, a voltage of the battery 120obtained when the anode potential of the battery 120 reaches a referencevalue is set to be the threshold voltage. The reference value may be setto be a specific value or interval, and the threshold voltage is set tomaintain the anode potential to be greater than or equal to thereference value while the battery 120 is being charged, and it is thuspossible to prevent metal plating on an anode of the battery 120 anddeterioration of the battery 120.

The battery charging apparatus 110 charges the battery 120 whilereducing the charging current stepwise each time a voltage of thebattery 120 reaches the threshold voltage. In response to the voltage ofthe battery 120 reaching a maximum voltage while the battery 120 isbeing charged in the step charging mode, the battery charging apparatus110 charges the battery 120 in a constant voltage charging mode.

Hereinafter, an example of a battery charging method performed by thebattery charging apparatus 110 will be described in detail withreference to FIGS. 2 and 3, and 4A and 4B.

FIGS. 2 and 3 are diagrams illustrating an example of a battery chargingmethod.

Referring to FIG. 2, in operation 210, the battery charging apparatus110 charges the battery 120 in a step charging mode. In this case, it isassumed that, when a step charging mode has charging currents, forexample, 1.2 C-rate to 0.4 C-rate as illustrated in Table 1, the batterycharging apparatus 110 charges the battery 120 with a charging current,for example, 1.2 C-rate, among the charging currents.

TABLE 1 Charging current (C-rate) 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4

In operation 220, the battery charging apparatus 110 monitors whether acurrent change event occurs to change the charging current. For example,the battery charging apparatus 110 monitors whether a voltage of thebattery 120 reaches a threshold voltage corresponding to the chargingcurrent, for example, 1.2 C-rate. That is, the battery chargingapparatus 110 compares the voltage of the battery 120 to the thresholdvoltage corresponding to the charging current, for example, 1.2 C-rate.The threshold voltage corresponding to 1.2 C-rate is a voltage of thebattery 120 at which an anode potential of the battery 120 reaches areference value. Thus, the battery charging apparatus 110 verifies thethreshold voltage corresponding to 1.2 C-rate to be, for example, 3.974V by referring to a table, for example, Table 2, in which chargingcurrents and corresponding threshold voltages are recorded, and thenmonitors whether the voltage of the battery 120 reaches the thresholdvoltage 3.974 V.

TABLE 2 Charging current Threshold voltage (C-rate) (V) 1.2 3.974 1.13.986 1.0 4.002 0.9 4.018 0.8 4.037 0.7 4.055 0.6 4.074 0.5 4.093 0.44.122

The reference value is set to prevent or minimize occurrence of metalplating on an anode of the battery 120. The reference value is set tobe, for example, a value in a range of 0.075 V to 0.73 V or 0.07 V to0.2 V. However, the reference value is not limited to the foregoingexample values.

In response to the current change event not occurring in operation 220,for example, in response to the voltage of the battery 120 being lessthan the threshold voltage 3.974 V, the battery charging apparatus 110continues charging the battery 120 with the charging current 1.2 C-rate.

In operation 230, in response to the current change event occurring inoperation 220, for example, in response to the voltage of the battery120 reaching the threshold voltage 3.974 V, the battery chargingapparatus 110 verifies whether the voltage of the battery 120 is lessthan a maximum voltage. The maximum voltage is set to preventovercharging of the battery 120, and may vary depending on a batterytype. For example, a maximum voltage of a lithium-ion battery may be setwithin a range of 4 V to 4.2 V. In a case in which the verifying ofwhether the voltage of the battery 120 is less than the maximum voltageis not performed, the battery 120 may be overcharged and becomeabnormal, and thus a life of the battery 120 may be reduced.Accordingly, the battery charging apparatus 110 verifies whether thevoltage of the battery 120 is less than the maximum voltage to preventor minimize such an overcharging issue.

In operation 240, in response to the voltage of the battery 120 beingless than the maximum voltage in operation 230, the battery chargingapparatus 110 changes the charging current. For example, the batterycharging apparatus 110 changes the charging current from 1.2 C-rate to1.1 C-rate. That is, the battery charging apparatus 110 terminates acharging interval corresponding to 1.2 C-rate, and charges the battery120 in a charging interval corresponding to 1.1 C-rate.

The battery charging apparatus 110 repeats operations 210 through 240until the voltage of the battery 120 reaches the maximum voltage. Whenthe battery charging apparatus 110 repetitively performs operations 210through 240, a change in voltage of the battery 120 may occur asillustrated in a graph 310 of FIG. 3. Referring to FIG. 3, the batterycharging apparatus 110 changes a charging current each time a currentchange event occurs until a voltage of the battery 120 reaches themaximum voltage.

In operation 250, in response to the voltage of the battery 120 reachingthe maximum voltage in operation 230, the battery charging apparatus 110charges the battery 120 with a constant voltage. That is, the batterycharging apparatus 110 charges the battery 120 in a constant voltagecharging mode. In this case, the charging current gradually decreasesover time to a termination current, for example, of 0.05 C-rate. Inoperation 260, in response to the charging current reaching thetermination current, the battery charging apparatus 110 terminatescharging the battery 120.

According to an example, charging in the step charging mode iscontrolled based on a threshold voltage, and thus an anode potential ofa battery is maintained to be greater than or equal to a referencevalue. Thus, occurrence of metal plating on an anode of the battery maybe prevented, and a life of the battery may therefore be increased.

FIGS. 4A and 4B are diagrams illustrating another example of a batterycharging method.

FIG. 4A illustrates tables 410, 420, and 430 corresponding to a state ofhealth (SOH) of 0.95, an SOH of 0.9, and an SOH of 0.85, respectively.The SOH is also referred to as life information of a battery.

An anode potential of the battery 120 changes depending on a degree ofdeterioration of the battery 120. However, when the battery chargingapparatus 110 continues charging the battery 120 using a single table,for example, Table 2 illustrated above, irrespective of the degree ofdeterioration of the battery 120, the anode potential may become lessthan a reference value. Thus, when the battery 120 deteriorates and anSOH of the battery 120 decreases accordingly, the battery chargingapparatus 110 performs the battery charging method described withreference to FIG. 2 above by referring to a table corresponding to thedecreased SOH. For example, referring to FIG. 4A, in a case in which theSOH of the battery 120 is 0.95, the battery charging apparatus 110performs the battery charging method described with reference to FIG. 2by referring to the table 410. In a case in which the SOH of the battery120 is 0.9, the battery charging apparatus 110 performs the batterycharging method described with reference to FIG. 2 by replacing thetable 410 with the table 420. Similarly, in a case in which the SOH ofthe battery 120 is 0.85, the battery charging apparatus 110 performs thebattery charging method described with reference to FIG. 2 by replacingthe table 420 with the table 430.

FIG. 4B illustrates tables 440, 450, and 460 corresponding to a batterytape a, a battery type b, and a battery type c, respectively. In each ofthe tables 440, 450, and 460, charging currents for a correspondingbattery type and threshold voltages corresponding to the chargingcurrents are recorded.

The battery charging apparatus 110 selects a table from various tablesbased on a battery type, and performs the battery charging methoddescribed with reference to FIG. 2 based on the selected table. Forexample, the battery charging apparatus 110 selects a table from thetables 440, 450, and 460 based on a type of the battery 120. The batterycharging apparatus 110 selects the table 440 in response to the type ofthe battery 120 being a, the table 450 in response to the type of thebattery 120 being b, and the table 460 in response to the type of thebattery 120 being c. The battery charging apparatus 120 then performsthe battery charging method described with reference to FIG. 2 based onthe selected table.

To perform the battery charging method described with reference to FIGS.1 through 3, and 4A and 4B by the battery charging apparatus 110, athreshold voltage corresponding to each charging current in a stepcharging mode may need to be determined in advance. Hereinafter, examplemethods of determining a threshold voltage be described in detail withreference to FIGS. 5 through 10.

FIGS. 5 through 7, and 8A and 8B are diagrams illustrating an example ofa method of determining a threshold voltage. The method of determining athreshold voltage to be described hereinafter may be performed by athreshold voltage determining apparatus.

Referring to FIG. 5, in operation 510, the threshold voltage determiningapparatus charges a reference battery in a normal charging mode. Thenormal charging mode is, for example, a constant current-constantvoltage (CCCV) based charging mode in which a C-rate is 0.3. In such anexample, the threshold voltage determining apparatus charges thereference battery with a constant current of 0.3 C-rate, and thencharges the reference battery with a constant voltage when a state ofcharge (SOC) of the reference battery reaches a preset SOC, for example,80%.

The reference battery used herein refers to a battery of a same type asthe battery 120, in which a reference electrode is inserted.

In operation 515, the threshold voltage determining apparatus measuresan anode potential of the reference battery being charged in the normalcharging mode. The anode potential refers to a difference between apotential of an anode of the reference battery and a potential of thereference electrode. The threshold voltage determining apparatusmeasures the anode potential until the reference battery is fullycharged.

In operation 520, the threshold voltage determining apparatus determinesa minimum value of the anode potential of the reference battery based ona result of the measuring of the anode potential. In operation 525, thethreshold voltage determining apparatus determines a reference valuebased on the minimum value. For example, referring to FIG. 6, thethreshold voltage determining apparatus determines a minimum value of0.1 V from an anode potential measuring result 610, and determines theminimum value of 0.1 V to be a reference value. Thus, in the exampleillustrated in FIG. 6, the reference value is 0.1.

The minimum value described in the foregoing is provided as an example,and thus may vary depending on a charging environment. For example, in acase in which a C-rate in the normal charging mode is 0.3, and atemperature of the anode is less than a room temperature, for example,when the temperature is −10° C., the minimum value of the anodepotential is 0.075 V. In a case in which a C-rate in the normal chargingmode is less than 0.3, and the temperature of the anode is greater thanthe room temperature, for example, when the temperature is 60° C., theminimum value of the anode potential is 0.73 V. In an example, when aC-rate in the normal charging mode increases at a same temperature ofthe anode, the minimum value of the anode potential decreases. Thus,based on the temperature of the anode and the C-rate in the normalcharging mode, the minimum value of the anode potential is set to be0.075 V to 0.73 V, for example. Also, based on the temperature of theanode being the room temperature and the C-rate being greater than 0.3,the minimum value of the anode potential is set to be 0.075 V to 0.2 V,for example. In addition, the minimum value of the anode potentialvaries depending on a type of the reference battery. For example, anelectrode active material, a thickness of an electrode, a porosity of anelectrode, an electrolyte, a current collector, a size of the referencebattery, and/or a maximum voltage of the reference battery varydepending on a type of the reference battery, and such factors describedin the foregoing description relate to the minimum value of the anodepotential. Thus, the minimum value of the anode potential differs amongtypes of the reference battery.

Referring to FIG. 5, in operation 530, when the reference value isdetermined, the threshold voltage determining apparatus discharges thereference battery. In this example, the threshold voltage determiningapparatus fully discharges the reference battery.

In operation 535, the threshold voltage determining apparatus chargesthe discharged reference battery with a charging current in a stepcharging mode. For example, the threshold voltage determining apparatuscharges the reference battery with a charging current of 1.2 C-rate inthe step charging mode as described above.

In operation 540, the threshold voltage determining apparatus compares,to a maximum voltage, a voltage of the reference battery being chargedwith the charging current in the step charging mode.

In operation 545, in response to the voltage of the reference batterybeing less than the maximum voltage, the threshold voltage determiningapparatus monitors whether the anode potential of the reference batteryreaches the reference value.

In response to the anode potential of the reference battery not reachingthe reference value as a result of the monitoring, the threshold voltagedetermining apparatus continues charging the reference battery with acharging current of 1.2 C-rate.

In operation 550, in response to the anode potential of the referencebattery reaching the reference value as the result of the monitoring,the threshold voltage determining apparatus determines the voltage ofthe reference battery to be a threshold voltage corresponding to thecharging current. In operation 555, the threshold voltage determiningapparatus changes the charging current. The threshold voltagedetermining apparatus repeats operations 535 through 555, and thenterminates charging the reference battery in operation 560 in responseto the voltage of the reference battery being greater than or equal tothe maximum voltage.

FIG. 7 illustrates a graph 710 indicating an anode potential based on aresult of repetitively performing operations 535 through 555. In thisexample, it is assumed that a voltage of the reference battery is 3.974V when the anode potential reaches a reference value 720 while thereference battery is being charged with a charging current of 1.2C-rate. The threshold voltage determining apparatus determines 3.974 Vto be a threshold voltage corresponding to 1.2 C-rate, and changes acharging current from 1.2 C-rate to 1.1 C-rate. When the anode potentialof the reference battery reaches the reference value 720 while thereference battery is being charged with a charging current of 1.1C-rate, the threshold voltage determining apparatus determines a voltageobtained when the anode potential reaches the reference value 720 to bea threshold voltage corresponding to 1.1 C-rate, and changes thecharging current from 1.1 C-rate to 1.0 C-rate. The threshold voltagedetermining apparatus repeats operations 535 through 555 to determine athreshold voltage corresponding to each of charging currents in the stepcharging mode, and completes a table in which the charging currents andcorresponding threshold voltages are recorded. The table is, forexample, Table 2 illustrated above.

According to an example, a reference electrode is inserted in varioustypes of batteries. In such a case, the threshold voltage determiningapparatus performs the method of determining a threshold voltage, whichis described with reference to FIG. 5, on the batteries in which thereference electrode is inserted and generates a table corresponding to atype of each of the batteries. The generated tables are, for example,the tables 440, 450, and 460 illustrated in FIG. 4B.

Referring back to FIG. 5, according to an example, the threshold voltagedetermining apparatus determines the reference value by adding a value ato the minimum value in operation 525. The value a is a constant value,which is greater than 0 and less than or equal to 0.1 (0<α≤0.1). In thisexample, a threshold voltage corresponding to a charging current isdetermined to be less than a threshold voltage obtained when thereference value is the minimum value, which will be described in detailwith reference to FIGS. 8A and 8B.

FIG. 8A illustrates a graph 810 indicating an anode potential based on aresult of repetitively performing operations 535 through 555 when areference value is 0.1, and a graph 820 indicating an anode potentialbased on the result of repetitively performing operations 535 through555 when a reference value is 0.11. Table 3 illustrates numerical valuesassociated with the graphs 810 and 820.

TABLE 3 Reference Reference value = value = 0.1 0.11 SOC (%) obtainedwhen an anode potential 38 26 reaches a reference value, in a case of acharging current being 1.2 C-rate SOC (%) obtained when an anodepotential 46 40 reaches a reference value, in a case of a chargingcurrent being 1.1 C-rate SOC (%) obtained when an anode potential 57 51reaches a reference value, in a case of a charging current being 1.0C-rate SOC (%) obtained when an anode potential 64 57 reaches areference value, in a case of a charging current being 0.9 C-rate SOC(%) obtained when an anode potential 73 62 reaches a reference value, ina case of a charging current being 0.8 C-rate SOC (%) obtained when ananode potential 79 70 reaches a reference value, in a case of a chargingcurrent being 0.7 C-rate ... ... ...

Referring to Table 3 above, in a situation in which a same chargingcurrent is given, an SOC obtained when the anode potential reaches thereference value of 0.11 is less than an SOC obtained when the anodepotential reaches the reference value of 0.1. That is, when the samecharging current flows in the reference battery, a voltage of thereference battery obtained when the anode potential reaches thereference value of 0.11 is less than a voltage of the reference batteryobtained when the anode potential reaches the reference value of 0.1. Avoltage of the reference battery obtained when the anode potentialreaches a reference value is determined to be a threshold voltage, andthus the threshold voltage is determined to be lower in a case in whichthe reference value is 0.11, as shown in the graph 820, than in a casein which the reference value is 0.1, as shown in the graph 810. FIG. 8Billustrates threshold voltages as squares when the reference value is0.1, and threshold voltages as circles when the reference value is 0.11.In this example, the threshold voltages obtained when the referencevalue is 0.11 are lower than the corresponding threshold voltagesobtained when the reference value is 0.1.

For example, as illustrated, when the battery charging method describedwith reference to FIG. 2 is performed with a threshold voltage generatedwhen the reference value is 0.11 as shown in the graph 820, a chargingcurrent changes when a voltage of the battery 120 reaches a lowthreshold voltage. Thus, the voltage of the battery 120 is controlled tobe low, and thus a period of time during which the battery 120 is usableincreases. Thus, by replacing a threshold voltage generated when thereference value is 0.1 with a threshold voltage generated when thereference value is 0.11, in Table 2 above, the battery charging methoddescribed with reference to FIG. 2 is performed.

FIGS. 9 and 10 are diagrams illustrating another example of a method ofdetermining a threshold voltage.

Referring to FIG. 9, in operation 910, when the voltage of the referencebattery reaches the maximum voltage in operation 540 described withreference to FIG. 5, the threshold voltage determining apparatusdischarges the reference battery. In this example, the reference voltageis fully discharged.

In operation 920, the threshold voltage determining apparatus verifieswhether a number of charging and discharging cycles of the dischargedreference battery corresponds to a preset number of times, for example,a number of 2 to 100 times. The threshold voltage determining apparatusperforms operation 920 to verify whether the reference batterydeteriorates to a preset degree of deterioration. In response to thenumber of charging and discharging cycles not corresponding to thepreset number of times in operation 920, the threshold voltagedetermining apparatus repeats operations 535 through 555, and operations910 and 920. That is, to deteriorate the reference battery to the presetdegree of deterioration, the threshold voltage determining apparatusrepeats operations 535 through 555, and operations 910 and 920. FIG. 10illustrates a result of repeating operations 535 through 555, andoperations 910 and 920. In detail, FIG. 10 illustrates a graph of arelationship between a charging current and a threshold voltage based oneach of the charging and discharging cycles, for example, a fifth cycle,a sixth cycle, and a tenth cycle. In response to the number of chargingand discharging cycles increasing, a threshold voltage is determined tobe lower. As described above, when the charging of the battery 120 iscontrolled based on the threshold voltage being determined to be low,the period of time during which the battery 120 is usable increases.

In response to the number of charging and discharging cyclescorresponding to the preset number of times in operation 920, thethreshold voltage determining apparatus terminates the charging. Forexample, in a case in which the number of charging and dischargingcycles corresponds to 76, the threshold voltage determining apparatusterminates the charging and generates a table indicating a relationshipbetween a charging current and a threshold voltage associated with a76th charging and discharging cycle. The generated table is stored inthe battery charging apparatus 110.

According to an example, the threshold voltage determining apparatusgenerates a table in which charging currents and corresponding thresholdvoltages are recorded for each time of the charging and dischargingcycles, and stores the generated table. That is, the threshold voltagedetermining apparatus generates such a table corresponding to an SOHthat decreases in response to an increase in a number of charging anddischarging cycles. The generated tables are, for example, the tables410, 420, and 430.

FIG. 11 is a diagram illustrating an example of the battery chargingapparatus 110. Referring to FIG. 11, the battery charging apparatus 110includes a controller 1110 and a memory 1120.

The controller 1110 charges the battery 120. For example, the controller1110 charges the battery 120 with a charging current in a step chargingmode.

In response to a current change event occurring while the battery 120 isbeing charged with the charging current, the controller 1110 changes thecharging current to a subsequent charging current.

The memory 1120 stores a table in which charging currents andcorresponding threshold voltages are recorded. The stored table is, forexample, Table 1 described with reference to FIG. 2. According to anexample, the memory 1120 stores the tables 410, 420, and 430 illustratedin FIG. 4A, and/or the tables 440, 450, and 460 illustrated in FIG. 4B.

The descriptions provided with reference to FIGS. 1 through 10 areapplicable to FIG. 11, and thus will not be repeated here.

FIG. 12 is a diagram illustrating an example of a threshold voltagedetermining apparatus 1200. Referring to FIG. 12, the threshold voltagedetermining apparatus 1200 includes a memory 1210 and a controller 1220.

The controller 1220 charges a reference battery in a step charging mode.In response to an anode potential of the reference battery reaching areference value while the reference battery is being charged in the stepcharging mode, the controller 1220 determines a voltage of the referencebattery to be a threshold voltage corresponding to a charging current,and changes the charging current. The controller 1220 performs such anoperation each time the anode potential of the reference battery reachesthe reference value. Thus, the controller 1220 determines a thresholdvoltage corresponding to each of charging currents in the step chargingmode, and generates a table in which the charging currents andcorresponding threshold voltages are recorded.

The memory 1210 stores the table generated by the controller 1220. Thetable generated by the threshold voltage determining apparatus 1200 isstored in the battery charging apparatus 110 described above, or abattery management system (BMS) to be described hereinafter.

The descriptions provided with reference to FIGS. 1 through 11 areapplicable to FIG. 12, and thus will not be repeated here.

FIG. 13 is a diagram illustrating an example of a vehicle 1300 includinga battery system 1310. Referring to FIG. 13, the vehicle 1300 uses abattery pack 1311 as a power source. The vehicle 1300 is, for example,an electric vehicle or a hybrid vehicle.

The battery system 1310 includes the battery pack 1311 and a BMS 1312.The battery charging apparatus 110 described above may be an off-boardcharger that corresponds to an external charger of the vehicle 1300. Insuch a case, the battery charging apparatus 110 is connected to thevehicle 1300 through a cable to charge the battery pack 1311. Accordingto an example, the battery charging apparatus 110 is an on-board chargerincluded in the vehicle 1300 or the BMS 1312.

The battery charging apparatus 110 controls the charging of the batterypack 1311 such that an anode potential of a battery cell included in thebattery pack 1311 is maintained to be greater than or equal to areference value. Thus, a life of the battery pack 1311 may be increased.

The descriptions provided with reference to FIGS. 1 through 12 areapplicable to FIG. 13, and thus will not be repeated here.

FIG. 14 is a diagram illustrating an example of a terminal 1400.Referring to FIG. 14, the terminal 1400 is connected to a power source1420.

The terminal 1400 may be a mobile terminal, such as, for example, asmartphone, a laptop computer, a tablet personal computer (PC), or awearable device. However, the terminal 1400 is not limited to theforegoing examples.

In an example, the battery charging apparatus 110 described above isincluded in the terminal 1400. For example, the battery chargingapparatus 110 is provided in the terminal 1400 in a form of anintegrated circuit (IC), and the terminal 1400 performs the batterycharging method described herein.

In another example, the battery charging apparatus 110 is included inthe power source 1420. In such an example, the power source 1420 isconnected to a charging port of the terminal 1400 through a wire orwirelessly. The power source 1420 operates in accordance with thebattery charging method described herein to charge a battery 1410 of theterminal 1400.

Although the battery 1410 is illustrated as being included in theterminal 1400 in FIG. 14, such an illustration is provided merely as anexample. For example, the battery 1410 may be separated from theterminal 1400 and connected to the power source 1420 to be charged.

The descriptions provided with reference to FIGS. 1 through 13 areapplicable to FIG. 14, and thus will not be repeated.

According to an example, an anode potential of a battery corresponds toan internal state of the battery, and therefore may not be readilymeasured while the battery is being charged. Thus, the anode potentialof the battery may be estimated, instead of being measured, during thecharging. For such estimation, an electrochemical model may be used.However, the electrochemical model requires a high performance, and thusa low-performance BMS and/or mobile terminal may not readily run such anelectrochemical model. The low-performance BMS and/or mobile terminalcan thus perform the battery charging method described herein, insteadof applying such an anode potential estimating method using theelectrochemical model. Accordingly, the low-performance BMS and/ormobile terminal can maintain the anode potential of the battery to begreater than or equal to a preset value while the battery is beingcharged, thereby improving a life of the battery.

The controller 1110, the memory 1120, the memory 1210, the controller1220, the battery system 1310, the BMS 1312, and the terminal 1400 inFIGS. 11-14 that perform the operations described in this applicationare implemented by hardware components configured to perform theoperations described in this application that are performed by thehardware components. Examples of hardware components that may be used toperform the operations described in this application where appropriateinclude controllers, sensors, generators, drivers, memories,comparators, arithmetic logic units, adders, subtractors, multipliers,dividers, integrators, and any other electronic components configured toperform the operations described in this application. In other examples,one or more of the hardware components that perform the operationsdescribed in this application are implemented by computing hardware, forexample, by one or more processors or computers. A processor or computermay be implemented by one or more processing elements, such as an arrayof logic gates, a controller and an arithmetic logic unit, a digitalsignal processor, a microcomputer, a programmable logic controller, afield-programmable gate array, a programmable logic array, amicroprocessor, or any other device or combination of devices that isconfigured to respond to and execute instructions in a defined manner toachieve a desired result. In one example, a processor or computerincludes, or is connected to, one or more memories storing instructionsor software that are executed by the processor or computer. Hardwarecomponents implemented by a processor or computer may executeinstructions or software, such as an operating system (OS) and one ormore software applications that run on the OS, to perform the operationsdescribed in this application. The hardware components may also access,manipulate, process, create, and store data in response to execution ofthe instructions or software. For simplicity, the singular term“processor” or “computer” may be used in the description of the examplesdescribed in this application, but in other examples multiple processorsor computers may be used, or a processor or computer may includemultiple processing elements, or multiple types of processing elements,or both. For example, a single hardware component or two or morehardware components may be implemented by a single processor, or two ormore processors, or a processor and a controller. One or more hardwarecomponents may be implemented by one or more processors, or a processorand a controller, and one or more other hardware components may beimplemented by one or more other processors, or another processor andanother controller. One or more processors, or a processor and acontroller, may implement a single hardware component, or two or morehardware components. A hardware component may have any one or more ofdifferent processing configurations, examples of which include a singleprocessor, independent processors, parallel processors,single-instruction single-data (SISD) multiprocessing,single-instruction multiple-data (SIMD) multiprocessing,multiple-instruction single-data (MISD) multiprocessing, andmultiple-instruction multiple-data (MIMD) multiprocessing.

The methods illustrated in FIGS. 2, 5, and 9 that perform the operationsdescribed in this application are performed by computing hardware, forexample, by one or more processors or computers, implemented asdescribed above executing instructions or software to perform theoperations described in this application that are performed by themethods. For example, a single operation or two or more operations maybe performed by a single processor, or two or more processors, or aprocessor and a controller. One or more operations may be performed byone or more processors, or a processor and a controller, and one or moreother operations may be performed by one or more other processors, oranother processor and another controller. One or more processors, or aprocessor and a controller, may perform a single operation, or two ormore operations.

Instructions or software to control computing hardware, for example, oneor more processors or computers, to implement the hardware componentsand perform the methods as described above may be written as computerprograms, code segments, instructions or any combination thereof, forindividually or collectively instructing or configuring the one or moreprocessors or computers to operate as a machine or special-purposecomputer to perform the operations that are performed by the hardwarecomponents and the methods as described above. In one example, theinstructions or software include machine code that is directly executedby the one or more processors or computers, such as machine codeproduced by a compiler. In another example, the instructions or softwareincludes higher-level code that is executed by the one or moreprocessors or computer using an interpreter. The instructions orsoftware may be written using any programming language based on theblock diagrams and the flow charts illustrated in the drawings and thecorresponding descriptions in the specification, which disclosealgorithms for performing the operations that are performed by thehardware components and the methods as described above.

The instructions or software to control computing hardware, for example,one or more processors or computers, to implement the hardwarecomponents and perform the methods as described above, and anyassociated data, data files, and data structures, may be recorded,stored, or fixed in or on one or more non-transitory computer-readablestorage media. Examples of a non-transitory computer-readable storagemedium include read-only memory (ROM), random-access memory (RAM), flashmemory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs, DVD-ROMs, DVD-Rs, DVD+Rs,DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs, BD-REs, magnetictapes, floppy disks, magneto-optical data storage devices, optical datastorage devices, hard disks, solid-state disks, and any other devicethat is configured to store the instructions or software and anyassociated data, data files, and data structures in a non-transitorymanner and provide the instructions or software and any associated data,data files, and data structures to one or more processors or computersso that the one or more processors or computers can execute theinstructions. In one example, the instructions or software and anyassociated data, data files, and data structures are distributed overnetwork-coupled computer systems so that the instructions and softwareand any associated data, data files, and data structures are stored,accessed, and executed in a distributed fashion by the one or moreprocessors or computers.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects in each example are to be considered as beingapplicable to similar features or aspects in other examples. Suitableresults may be achieved if the described techniques are performed in adifferent order, and/or if components in a described system,architecture, device, or circuit are combined in a different manner,and/or replaced or supplemented by other components or theirequivalents. Therefore, the scope of the disclosure is defined not bythe detailed description, but by the claims and their equivalents, andall variations within the scope of the claims and their equivalents areto be construed as being included in the disclosure.

What is claimed is:
 1. A terminal, comprising: a battery; and anintegrated circuit (IC) configured to charge the battery with a chargingcurrent, and to change the charging current when the battery reaches athreshold voltage set to maintain an anode potential of the battery tobe greater than or equal to a reference value during the charging of thebattery.
 2. The terminal of claim 1, wherein the IC comprises: a memoryconfigured to store charging currents and corresponding thresholdvoltages; and a controller configured to change the charging currentreferring to the stored threshold voltages.
 3. The terminal of claim 1,wherein the IC is further configured to verify the threshold voltagecorresponding to the charging current by referring to a table in whichthe threshold voltage and the charging current are stored.
 4. Theterminal of claim 3, wherein the IC is further configured to replace thetable, in response to life information of the battery changing, with atable corresponding to the changed life information.
 5. The terminal ofclaim 1, wherein the IC is further configured to terminate a charginginterval corresponding to the charging current when the battery reachesthe threshold voltage and to charge the battery with a current that isless than the charging current in a subsequent charging interval.
 6. Theterminal of claim 1, wherein the IC is further configured to charge thebattery with a constant voltage, in response to the battery reaching amaximum voltage, and to terminate the charging of the battery, inresponse to the charging current decreasing to a termination currentduring the charging of the battery with the constant voltage.
 7. Theterminal of claim 1, wherein the reference value is 0.075 volts (V) to0.73 V.
 8. The terminal of claim 1, wherein the reference value is 0.075V to 0.2 V.
 9. A power source configured to charge a battery of aterminal, comprising: an integrated circuit (IC) configured to chargethe battery with a charging current, and to change the charging currentwhen the battery reaches a threshold voltage set to maintain an anodepotential of the battery to be greater than or equal to a referencevalue during the charging of the battery.
 10. The power source of claim9, wherein the IC comprises: a memory configured to store chargingcurrents and corresponding threshold voltages; and a controllerconfigured to change the charging current referring to the storedthreshold voltages.
 11. The power source of claim 9, wherein the IC isfurther configured to verify the threshold voltage corresponding to thecharging current by referring to a table in which the threshold voltageand the charging current are stored.
 12. The power source of claim 9,wherein the IC is configured to replace the table, in response to lifeinformation of the battery changing, with a table corresponding to thechanged life information.
 13. The power source of claim 9, wherein theIC is configured to terminate a charging interval corresponding to thecharging current and to charge the battery with a current that is lessthan the charging current in a subsequent charging interval, when thebattery reaches the threshold voltage.
 14. The power source of claim 9,wherein the IC is configured to charge the battery with a constantvoltage in response to the battery reaching a maximum voltage, and toterminate the charging of the battery in response to the chargingcurrent decreasing to a termination current during the charging of thebattery with the constant voltage.
 15. The power source of claim 9,wherein the reference value is 0.075 volts (V) to 0.73 V.
 16. The powersource of claim 9, wherein the reference value is 0.075 V to 0.2 V.